Just as Senate Democrats were sitting down Thursday to a scheduled meeting with White House budget director Jacob J. Lew, rumors of a new debt-limit deal between President Obama and House Speaker John A. Boehner (R-Ohio) flashed across their BlackBerrys.

One after another, Sens. John F. Kerry (Mass.), Barbara A. Mikulski (Md.), Maria Cantwell (Wash.) and others demanded that Lew explain what the president was doing.

The Democrats were winning, the senators said. The American people were with them on tax increases for the rich and the notion of “shared sacrifice.” Why give up now? Why cut a deal without guarantees of new tax revenue?

For 45 minutes, the cross-examination went on, with few details offered. When Lew left, Mikulski turned to her colleagues and said, “I haven’t seen a meeting like this in my 35 years in Congress.”

Outside the room, Lew said he was “not aware of a deal.”

For the first time in weeks of debt negotiations that have focused on rifts within the Republican Party, Thursday brought forward long-simmering tensions between Obama and his Democratic allies on Capitol Hill.

With more concerns than details, Democrats lashed out, saying that deep cuts to federal agency budgets and entitlements were too steep a price to pay. They questioned whether Obama shared their core values, and they sought reassurance — at a hastily arranged evening meeting at the White House that lasted nearly two hours — that the final legislative package would be the balanced approach that the president had promised.

“There has to be a balance. There has to be some revenue and cuts. My caucus agrees with that. I hope that the president sticks with that,” Senate Majority Leader Harry M. Reid (Nev.) told reporters.

In the House, rank-and-file Democrats said the situation had grown dire.

“It would concern me greatly if these folks — the tea party group — have been able to convince the president to go along with a deal that basically gives them everything they want but yet still takes away from those who are our most vulnerable,” said. Rep. Elijah E. Cummings (Md.), a former chairman of the Congressional Black Caucus.

“The people that I’m talking about, when you’re talking about Medicaid, Medicare and Social Security — and I’m sure they’re all mixed up in there in this $3 trillion — those are people, a lot of whom are in my district, who have no alternatives,” he continued. “They’re not the guys who own the planes; they’re not the ones who fly off to Paris for vacation.”

Rep. Raul M. Grijalva (Ariz.), a leader of the House Progressive Caucus, said: “We feel like the programs we care about are on the table. The other side’s priorities that the American public thinks should be dealt with — tax cuts, corporate subsidies — are not on the table.”

Often kept in check out of loyalty for their president, congressional Democrats have grown increasingly suspicious of Obama’s motives over the past year.

Many in the House didn’t appreciate what they saw as meager support for Nancy Pelosi (Calif.) in her final, embattled months as House speaker before the 2010 midterm election.

Among Senate Democrats, there is still bitterness about the deal Vice President Biden negotiated in secret in December with Senate Minority Leader Mitch McConnell (R-Ky.) that extended all of the George W. Bush-era tax cuts, including those for the wealthy.

The T-word — “triangulation” — began to circulate across Capitol Hill as lawmakers recalled how President Bill Clinton distanced himself from his party’s liberal base and from conservatives as he positioned himself for a reelection run.

White House officials rejected the idea Thursday that they were abandoning their allies and said Obama was still seeking fresh tax revenue in a final deal.

“It is absolutely essential that any ‘grand bargain,’ if you will, any significantly sized deficit-reduction package be balanced; that it contain — that it address all the drivers of our long-term debt and our significant deficits,” White House press secretary Jay Carney told reporters.

Pelosi, now the House minority leader, stayed largely silent ahead of the White House meeting, which was designed in part to ease nerves on the left. One of her top advisers suggested that it was still too soon to think the president would agree to such a proposal, given that the final deal is likely to need dozens of Democratic votes because so many House Republicans remain opposed to raising the debt ceiling under any circumstances.

“If they think they can do it with 218 Republicans, let's see it,” said Rep. Steve Israel (N.Y.), chairman of the Democratic Congressional Campaign Committee.

Republicans didn’t mind seeing a little open feuding on the other side of the aisle. Throughout July, the Capitol has been absorbed by a GOP soap opera as Boehner has privately jousted with his younger leadership lieutenants. In the Senate, allies of McConnell have made clear his concern that the speaker would pursue a deal that includes new tax revenue.

Exiting his own GOP luncheon Thursday, a smiling McConnell greeted reporters by confirming only that he “had lunch,” deflecting questions about the debt talks. House Majority Leader Eric Cantor (Va.), the most outspoken GOP critic of any broad deal, also found nothing to denounce.

“There are all kinds of options on the table,” he told reporters.

Among the Democrats, it was the senators who were most vocal in their criticism of a president who used to be one of them. Reid’s statement — unusual in its form, delivered at an impromptu setting just off the Senate floor minutes after Lew’s hasty exit — set the tone for how his caucus felt about any deal without tax increases of some form.

Sen. Frank R. Lautenberg (N.J.) noted “a little separation” between Obama and his former Senate caucus. Sen. Dianne Feinstein (Calif.) pleaded to return to negotiations over a Reid-McConnell plan that contained no tax increases and no entitlement cuts.

“This is a very sensitive time,” she said, trying not to directly criticize the White House.